Mei Aihara: Shō has a strained relationship with his daughter, after leaving her to the care of her grandfather to travel the world. However, he was shown to deeply care for his daughter, but have difficulty to demonstrate it, which he admits to. Mei has the habit of calling him "sensei" (teacher) instead of "father", which bothers him.
Yuzu Aihara: Although Yuzu is initially surprised by his appearance, she quickly realizes he's a nice person 
Yuzu's Mother: He has a good relationship with her, despite not usually being at home. She teases him for not being able to talk to his own daughter normally, and even calls him a Tsundere.